A monument commemorates Mannalargenna, the last chief of the Portland tribe. The plaque is on the the same monument as the first European child born in Tasmania.

Mannalargenna (died 1835), Aboriginal leader, led the Cape Portland people. After Europeans moved into the area and took the Aborigines' land, Mannalargenna used his detailed knowledge of the terrain to resist this invasion and destroy their property. In 1829 he freed four Aboriginal women and a boy from John Batman's house, where they had been kept since they were captured a year before.

In 1830, Mannalargenna voluntarily joined G.A. Robinson's 'friendly mission', but, although he was supposed to be helping Robinson persuade Aboriginal people to surrender, in fact he led Robinson in circles away from them, and would go hunting when Robinson needed him. Mannalargenna consulted a Spirit about the location of Aboriginal groups, which continually misled him, to Robinson's fury.

Although Robinson had promised that if Mannalargenna helped him he would not be sent to the Flinders Island establishment, the promise was broken, and Mannalargenna died in captivity.